Method for measuring pressure relief range of pressure relief borehole

Abstract

This invention provides a method for measuring the pressure relief range of a pressure relief borehole. The method includes acquiring the initial strain value of a sensing optical fiber, then repeatedly acquiring real-time strain values ​​at multiple acquisition points on the sensing optical fiber to obtain multiple strain value variations obtained from the same acquisition and with stable average values. These multiple strain value variations include alternating negative and non-negative segments. The pressure relief radius R of the pressure relief borehole is calculated according to a formula, where h is the distance between the center point of the pressure relief borehole and the sensing optical fiber, and L is the length of the corresponding non-negative segment on the sensing optical fiber. This invention's method for measuring the pressure relief range of a pressure relief borehole can calculate the pressure relief radius of the borehole. The pressure relief radius can be used to determine whether the pressure relief effect after drilling is qualified, and can also be used to set the density of the drilled pressure relief borehole.

Description

Technical Field

[0001] This invention relates to the field of rock and soil pressure relief, and specifically to a method for measuring the pressure relief range of a pressure relief borehole. Background Technology

[0002] In the mining of minerals such as coal mines, rock bursts can pose safety hazards, and drilling pressure relief boreholes is one of the effective measures to relieve pressure and mitigate these hazards. However, related technologies suffer from difficulties in determining the pressure relief effect after drilling, as well as the degree of compaction required during the drilling process. Summary of the Invention

[0003] The present invention aims to at least partially solve one of the technical problems in the related art.

[0004] Therefore, embodiments of the present invention propose a method for measuring the pressure relief range of a pressure relief borehole.

[0005] The method for measuring the pressure relief range of a pressure relief borehole according to an embodiment of the present invention includes:

[0006] Optical fiber arrangement holes are set in the rock mass, and sensing optical fibers are placed in the optical fiber arrangement holes.

[0007] The optical fiber arrangement hole is sealed, and then grouting material is injected into the optical fiber arrangement hole;

[0008] A pressure relief borehole is set in the rock mass, and the pressure relief borehole is located below the optical fiber arrangement hole;

[0009] When the grouting material solidifies, the initial strain value of the sensing optical fiber is collected by an optical time domain reflectometer.

[0010] The optical time domain reflectometer collects real-time strain values ​​at multiple points on the sensing fiber, and collects them multiple times in sequence. The difference between each real-time strain value collected and the initial strain value is calculated to obtain the strain value variation corresponding to each collection. The collection of real-time strain values ​​is stopped when the strain value variation values ​​obtained in the same collection are all stable.

[0011] The multiple strain value variations obtained from the same acquisition and with stable values ​​include alternating negative and non-negative segments. The negative segments include multiple strain value variations that are continuously negative, and the non-negative segments include multiple strain value variations that are continuously non-negative. The non-negative segments located between the beginning and the end of the negative segments correspond to the pressure relief borehole.

[0012] According to the formula The pressure relief radius R of the pressure relief borehole is calculated, where h is the distance between the center point of the pressure relief borehole and the sensing optical fiber, and L is the length of the non-negative segment corresponding to the pressure relief borehole on the sensing optical fiber.

[0013] The pressure relief range measurement method of the pressure relief borehole in this embodiment of the invention uses an optical time domain reflectometer to collect the initial strain value and real-time strain value of the sensing optical fiber located in the optical fiber arrangement hole, so as to obtain the variation of multiple strain values ​​obtained in the same acquisition and with stable values, thereby calculating the pressure relief radius of the pressure relief borehole. The pressure relief radius of the pressure relief borehole can be used to judge whether the pressure relief effect after the pressure relief borehole is qualified, and can also be used to set the density of the pressure relief borehole.

[0014] In some embodiments, there are at least two pressure relief holes, and the at least two pressure relief holes are arranged at intervals along the length direction of the optical fiber arrangement hole.

[0015] There are at least two non-negative segments located between the beginning and the end of the negative segments, and along the length direction of the optical fiber arrangement hole, at least two non-negative segments correspond sequentially to at least two pressure relief drill holes;

[0016] According to the formula The pressure relief radius R of each of the pressure relief boreholes is calculated.

[0017] In some embodiments, at least two of the pressure relief boreholes have the same diameter; or

[0018] In at least two of the aforementioned pressure relief boreholes, some of the boreholes have the same diameter; or

[0019] In at least two of the aforementioned pressure relief boreholes, the diameter of each pair of the pressure relief boreholes is different.

[0020] In some embodiments, when the change in strain value among the multiple strain value changes obtained in a later acquisition is less than or equal to 1% compared to the change in strain value obtained in a previous acquisition at the same acquisition point, and when the change in strain value among the multiple strain value changes obtained in a later acquisition is negative or non-negative compared to the change in strain value obtained in a previous acquisition at the same acquisition point, the acquisition of the real-time strain value is stopped.

[0021] The strain values ​​obtained from the last acquisition before the acquisition of the real-time strain values ​​were stopped were all stable and included alternating negative and non-negative segments, thereby obtaining the length of the non-negative segment corresponding to the pressure relief borehole on the sensing optical fiber.

[0022] In some embodiments, the distance between the projection of the pressure relief drill hole and the projection of the optical fiber arrangement hole in the vertical projection plane is 0.3m to 0.5m.

[0023] In some embodiments, a chamber is provided in the rock mass, and the optical fiber arrangement hole is drilled in the wall of the chamber. The optical fiber arrangement hole extends parallel to the rock mass or extends obliquely along the rock mass, and the distance between the optical fiber arrangement hole and the rock mass is greater than or equal to 2m.

[0024] In some embodiments, the pressure relief borehole is drilled in the rock mass sidewall. In the horizontal projection plane, the projection of the pressure relief borehole intersects with the projection of the optical fiber arrangement hole. The depth of the pressure relief borehole from the sidewall is greater than the maximum distance between the optical fiber arrangement hole and the sidewall.

[0025] In some embodiments, the sensing optical fiber is disposed on a flexible mounting tube, which is inserted into the optical fiber arrangement hole so that the sensing optical fiber is disposed in the optical fiber arrangement hole and extends from the opening of the optical fiber arrangement hole to the bottom of the optical fiber arrangement hole.

[0026] In some embodiments, after the mounting tube is inserted into the optical fiber arrangement hole, the grouting tube is inserted into the optical fiber arrangement hole and arranged side by side with the mounting tube;

[0027] After the optical fiber arrangement hole is sealed, grouting material is injected into the optical fiber arrangement hole through the grouting pipe, and the injection of grouting material is stopped when the grouting material is discharged through the installation pipe.

[0028] In some embodiments, the optical time-domain reflectometer is connected to the sensing fiber via a communication fiber to acquire the initial strain value and the real-time strain value of the sensing fiber; and / or

[0029] The acquisition frequency of the optical time domain reflectometer is less than or equal to 0.1 m. Attached Figure Description

[0030] Figure 1 This is a construction schematic diagram of the pressure relief range measurement method for pressure relief drilling according to an embodiment of the present invention;

[0031] Figure 2 yes Figure 1 A partially enlarged schematic diagram;

[0032] Figure 3 This is a schematic diagram showing the relative positions of the fiber optic arrangement hole, the pressure relief drill hole, and the roadway side in the horizontal projection plane in an embodiment of the present invention.

[0033] Figure 4 This is a schematic diagram of the sensing optical fiber and the mounting tube in an embodiment of the present invention.

[0034] Figure label:

[0035] 1. Working face; 2. Track roadway; 3. Return air roadway; 4. Sensor fiber optic; 5. Communication fiber optic; 6. Flange; 7. Air door; 8. Optical time domain reflectometer; 9. Fiber optic mounting hole; 10. Chamber; 11. Roadway side; 12. Installation pipe; 13. Through hole; 14. Binding wire; 15. Cable tie; 16. Pressure relief drill hole. Detailed Implementation

[0036] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0037] The following is for reference. Figures 1-4 A method for measuring the pressure relief range of a pressure relief borehole according to an embodiment of the present invention is described.

[0038] like Figures 1-4 As shown, the method for measuring the pressure relief range of a pressure relief borehole according to an embodiment of the present invention includes:

[0039] An optical fiber arrangement hole 9 is set in the rock mass, and a sensing optical fiber 4 is installed inside the optical fiber arrangement hole 9.

[0040] The fiber optic routing hole 9 is sealed, and then grouting material is injected into the fiber optic routing hole 9.

[0041] A pressure relief borehole 16 is set in the rock mass, and the pressure relief borehole 16 is located below the fiber optic arrangement hole 9.

[0042] When the grouting material solidifies, the initial strain value of the sensing fiber 4 is collected by the optical time domain reflectometer 8.

[0043] The optical time domain reflectometer 8 collects real-time strain values ​​from multiple points on the sensing fiber 4, and collects them multiple times in sequence. The difference between each real-time strain value and the initial strain value is calculated to obtain the strain value variation corresponding to each collection. The collection of real-time strain values ​​is stopped when the strain value variation values ​​obtained in the same collection are all stable.

[0044] Specifically, multiple acquisition points are arranged at intervals along the length of the sensing fiber 4, and the interval between adjacent acquisition points is determined by the acquisition frequency of the optical time domain reflectometer 8.

[0045] The multiple strain value variations obtained from the same acquisition and with stable values ​​include alternating negative and non-negative segments. The negative segment includes multiple strain value variations that are consecutively negative; in other words, all strain value variations in the negative segment are negative. The non-negative segment includes multiple strain value variations that are consecutively non-negative; in other words, all strain value variations in the non-negative segment are non-negative, and these non-negative strain value variations can be positive or zero. The non-negative segment located between the beginning and end of the negative segment corresponds to the pressure relief borehole 16.

[0046] According to the formula The pressure relief radius R of the pressure relief borehole 16 is calculated, where h is the distance between the center point of the pressure relief borehole 16 and the sensing fiber 4, and L is the arrangement length of the non-negative segment corresponding to the pressure relief borehole 16 on the sensing fiber 4. In other words, L is the arrangement length of the multiple acquisition points corresponding to all the multiple strain value changes in the non-negative segment corresponding to the pressure relief borehole 16 on the sensing fiber 4.

[0047] It should be noted that the length of the multiple sampling points corresponding to the multiple strain value changes in the negative segment did not undergo tensile deformation on the length of the sensing fiber 4, while the length of the multiple sampling points corresponding to the multiple strain value changes in the non-negative segment did undergo tensile deformation. Therefore, the arrangement length of the non-negative segment on the sensing fiber 4 is used to calculate the pressure relief radius R of the pressure relief borehole 16, while the negative segment is used to divide the non-negative segment.

[0048] It should be noted that in multiple real-time strain value acquisitions, the interval between two adjacent acquisitions can be the same or different.

[0049] The pressure relief range measurement method of the pressure relief borehole 16 in this embodiment of the invention uses an optical time domain reflectometer to collect the initial strain value and real-time strain value of the sensing optical fiber located in the optical fiber arrangement hole, so as to obtain the variation of multiple strain values ​​obtained in the same acquisition and with stable values, thereby calculating the pressure relief radius of the pressure relief borehole. The pressure relief radius of the pressure relief borehole can be used to judge whether the pressure relief effect after the pressure relief borehole is qualified, and can also be used to set the density of the pressure relief borehole.

[0050] In some embodiments, a chamber 10 is provided in the rock mass sidewall 11, and fiber optic arrangement holes 9 are drilled in the wall of the chamber 10. The fiber optic arrangement holes 9 extend parallel to the sidewall 11 or extend obliquely along the sidewall 11, and the distance between the fiber optic arrangement holes 9 and the sidewall 11 is greater than or equal to 2m.

[0051] like Figure 1 and Figure 2As shown, the rock mass is preferably, but not limited to, a coal seam. The coal seam includes a working face 1 and a roadway. The roadway includes a return air roadway 3. A chamber 10 is provided in the sidewall 11 of the return air roadway 3. Optical fiber arrangement holes 9 are drilled in the wall of the chamber 10. The optical fiber arrangement holes 9 can extend parallel to the sidewall 11 or extend obliquely along the sidewall 11. In other words, the extension direction of the optical fiber arrangement holes 9 can be parallel to the extension direction of the sidewall 11 or have a certain angle. Preferably, as shown... Figure 2 As shown, the fiber optic arrangement hole 9 extends along the sidewall 11 and is inclined in a direction away from the return airway 3. The angle between the extension direction of the fiber optic arrangement hole 9 and the extension direction of the sidewall 11 is 2° to 10°, preferably but not limited to 5°.

[0052] The distance between the fiber optic cable placement hole 9 and the roadway side 11 is greater than or equal to 2m. In other words, the distance between any position of the fiber optic cable placement hole 9 along its length and the roadway side 11 is greater than or equal to 2m.

[0053] The fiber optic placement hole 9 is drilled on the wall of the chamber 10 to facilitate construction and to ensure the reliability of the obtained pressure relief radius R value. The distance between the fiber optic placement hole 9 and the tunnel wall 11 is greater than or equal to 2m, which also ensures the reliability of the obtained pressure relief radius R value.

[0054] In some embodiments, the sensing fiber 4 is disposed on a flexible mounting tube 12, which is inserted into the fiber arrangement hole 9 so that the sensing fiber 4 is disposed in the fiber arrangement hole 9 and extends from the opening of the fiber arrangement hole 9 to the bottom of the hole.

[0055] like Figure 1 , Figure 2 and Figure 4 As shown, the sensing fiber 4 is mounted on the flexible mounting tube 12. When the working surface 1 undergoes changes such as settlement, the mounting tube 12 bends and deforms along with the fiber arrangement hole 9, thereby causing the sensing fiber 4 to bend and deform, which is then collected by the optical time domain reflectometer 8 and the non-negative strain value change is obtained.

[0056] The worker inserts the mounting tube 12, which contains the sensing fiber 4, into the fiber optic arrangement hole 9, bringing it abutting against the bottom of the hole. This ensures that the sensing fiber 4 is positioned within the hole, extending from the opening to the bottom. In other words, one end of the sensing fiber 4 is at the bottom of the hole, and the other end is at the opening. This allows the multiple real-time strain values ​​of the sensing fiber 4 collected by the optical time-domain reflectometer 8 to fully reflect the deformation of the fiber optic arrangement hole 9.

[0057] It should be noted that one end of the mounting tube 12 and one end of the sensing fiber 4 are both located at the bottom of the fiber arrangement hole 9. The other end of the mounting tube 12 and the other end of the sensing fiber 4 can both be located in the opening of the fiber arrangement hole 9. The other end of the mounting tube 12 can also be located inside the opening of the fiber arrangement hole 9. In other words, the length of the mounting tube 12 can be the same as the length of the fiber arrangement hole 9, or it can be shorter than the length of the fiber arrangement hole 9.

[0058] In some embodiments, after the mounting tube 12 is inserted into the optical fiber arrangement hole 9, the grouting tube is inserted into the optical fiber arrangement hole 9 and arranged side by side with the mounting tube 12. After the optical fiber arrangement hole 9 is sealed, grouting material is injected into the optical fiber arrangement hole 9 through the grouting tube, and the injection of grouting material is stopped when the grouting material is discharged through the mounting tube 12.

[0059] Specifically, after the worker inserts the installation tube 12 into the optical fiber arrangement hole 9, the worker then inserts the grouting tube into the optical fiber arrangement hole 9. The grouting tube and the installation tube 12 are arranged side by side in the optical fiber arrangement hole 9. During the insertion of the grouting tube, care should be taken to avoid touching and damaging the sensing optical fiber 4.

[0060] After the grouting pipe is inserted into the optical fiber arrangement hole 9, the optical fiber arrangement hole 9 is sealed. The sealing material is preferably, but not limited to, polyurethane.

[0061] After sealing the fiber optic routing hole 9, preferably but not limited to, after the polyurethane has solidified, the grouting pump connected to the grouting pipe is turned on to inject grouting material into the fiber optic routing hole 9 through the grouting pipe. The grouting pump is turned off to stop injecting grouting material when the grouting material is discharged back through the installation pipe 12. This ensures that the fiber optic routing hole 9 is completely filled with grouting material, thereby ensuring that the installation pipe 12 can bend and deform with the deformation of the fiber optic routing hole 9 when changes occur on the working surface 1, such as settlement.

[0062] The preferred grouting material is, but not limited to, cement mortar. The specific mix proportion of the cement mortar is set according to the parameters of the coal seam, and preferably the elastic modulus of the cement mortar is ±5% of the elastic modulus of the coal seam.

[0063] It is understood that in other embodiments, the mounting tube and the grouting tube may also be inserted together into the fiber optic routing hole.

[0064] In some embodiments, the mounting tube 12 is preferably, but not limited to, a PVC pipe, and the sensing optical fiber 4 is preferably, but not limited to, bundled around the outer wall of the mounting tube 12, such as... Figure 4 As shown.

[0065] Specifically, the mounting tube 12 includes a tip, an open section, and a closed section connected sequentially along its length. The cavity of the mounting tube 12 is located at least within the open section and the closed section, and an opening is formed at the end of the closed section away from the open section. The tip is closed to facilitate insertion into the optical fiber arrangement hole 9 and fixation to the bottom of the hole 9. The length of the closed section is 5 times or more the length of the open section. The wall of the open section is provided with multiple through holes 13, which communicate with the cavity of the mounting tube 12.

[0066] The grouting material injected into the optical fiber arrangement hole 9 through the grouting pipe enters the cavity of the installation pipe 12 through the through hole 13, then flows back along the cavity of the installation pipe 12 and is discharged from the pipe opening of the installation pipe 12.

[0067] By setting a through hole 13 in the opening section and sealing the tip, it is possible to ensure that the grouting material enters the cavity of the installation pipe 12 through the through hole 13. This avoids the situation where the inlet of the grouting material is set at the tip, and the inlet of the grouting material is blocked due to the tip being inserted into the bottom of the optical fiber arrangement hole 9, thus preventing it from entering the cavity of the installation pipe 12.

[0068] The sensing fiber 4 is bundled to the outer wall of the open section and the closed section. Preferably, the sensing fiber 4 is bundled with binding wire 14 and cable tie 15 on the open section. The binding wire 14 and cable tie 15 on the open section are arranged alternately and spaced apart along the length of the open section. The sensing fiber 4 is bundled with spaced-apart cable ties 15 on the closed section. This ensures the stable installation of the sensing fiber 4 and avoids damage to the sensing fiber 4. It should be noted that the cable tie 15 is made of plastic and the binding wire 14 is made of metal.

[0069] In some embodiments, the diameter of the sensing fiber 4 is preferably, but not limited to, 5.0 ± 0.2 mm, the strain coefficient is preferably, but not limited to, not less than 499.8 MHz / , the maximum breaking force is preferably, but not limited to, not less than 2350 N, and the sensing fiber 4 is preferably, but not limited to, a metal substrate.

[0070] In some embodiments, a pressure relief borehole 16 is drilled in the rock wall 11. In the horizontal projection plane, the projection of the pressure relief borehole 16 intersects with the projection of the optical fiber arrangement hole 9. The depth of the pressure relief borehole 16 from the rock wall 11 is greater than the maximum distance between the optical fiber arrangement hole 9 and the rock wall 11.

[0071] like Figure 2 and Figure 3 As shown, a pressure relief borehole 16 is drilled in the rock mass tunnel sidewall 11. The pressure relief borehole 16 extends in the front-to-back direction, and the fiber optic arrangement hole 9 extends in the left-to-right direction.

[0072] It should be noted that the pressure relief borehole 16 can extend horizontally in the front-back direction, or it can have a certain angle of inclination in the vertical direction and / or the left-right direction, preferably extending in the front-back direction.

[0073] The fiber optic arrangement hole 9 can extend horizontally in the left-right direction, or it can have a certain tilt angle in the vertical direction and / or the front-back direction. Preferably, it extends in the left-right direction, has a 5° angle with the roadway wall in the front-back direction, and has a 1° angle in the vertical direction.

[0074] Within the horizontal projection plane, such as Figure 3 As shown, the projection of the pressure relief borehole 16 intersects with the projection of the fiber optic arrangement hole 9. The depth of the pressure relief borehole 16 from the roadway side 11 is W3. The fiber optic arrangement hole 9 and the roadway side 11 have a minimum distance W1 and a maximum distance W2, with W2 being less than W3, to ensure that the obtained pressure relief radius R value is reliable.

[0075] In some embodiments, the distance between the projection of the pressure relief drill hole 16 and the projection of the fiber optic arrangement hole 9 in the vertical projection plane is 0.3m to 0.5m. In other words, the highest position of the pressure relief drill hole 16 in the vertical direction is lower than the lowest position of the fiber optic arrangement hole 9 in the vertical direction, and the height difference between the highest position of the pressure relief drill hole 16 in the vertical direction and the lowest position of the fiber optic arrangement hole 9 in the vertical direction is 0.3m to 0.5m. This ensures that the obtained pressure relief radius R value is reliable.

[0076] In some embodiments, the optical time domain reflectometer 8 is connected to the sensing fiber 4 via the communication fiber 5 to acquire the initial strain value and real-time strain value of the sensing fiber 4.

[0077] like Figure 1 As shown, the optical time domain reflectometer 8 is connected to the sensing fiber 4 via the communication fiber 5. Specifically, the connection can be made after the grouting material is poured, or after the sensing fiber 4 is inserted into the fiber arrangement hole 9 via the installation tube 12. Preferably, the connection is made after the grouting material is poured.

[0078] The communication fiber 5 and the sensing fiber 4 are preferably, but not limited to, assisted by a flange 6. Since the sensing fiber 4 is located inside the fiber arrangement hole 9, the flange 6 is located at the opening of the fiber arrangement hole 9.

[0079] The coal seam roadway also includes track roadway 2. The optical time domain reflectometer 8 is preferably, but not limited to, located in track roadway 2. The communication optical fiber 5 reaches track roadway 2 from return air roadway 3 through air door 7 and is connected to optical time domain reflectometer 8 to transmit the signal of sensing optical fiber 4 to optical time domain reflectometer 8.

[0080] In some embodiments, the sampling frequency of the optical time-domain reflectometer 8 is less than or equal to 0.1 m, preferably but not limited to 0.1 m. In other words, the distance between adjacent sampling points is less than or equal to 0.1 m, preferably but not limited to 0.1 m. This ensures that the obtained pressure relief radius R value is reliable.

[0081] In some embodiments, there are at least two pressure relief holes 16, and the at least two pressure relief holes 16 are arranged at intervals along the length direction of the optical fiber arrangement hole 9. Specifically, as shown in the figure Figure 3 As shown, the pressure relief drill holes 16 are preferably, but not limited to, multiple, and the multiple pressure relief drill holes 16 are arranged at intervals in the left-right direction. It is understood that in some other embodiments, there may be only one pressure relief drill hole 16.

[0082] There are at least two non-negative segments located between the initial negative segment and the final negative segment. Along the length of the fiber optic arrangement hole 9, at least two non-negative segments correspond sequentially to at least two pressure relief drill holes 16. Specifically, the negative and non-negative segments are arranged alternately along the length of the corresponding fiber optic arrangement hole 9. The first negative segment is the initial negative segment, and the last negative segment is the final negative segment. The non-negative segments between the initial and final negative segments are multiple segments sequentially corresponding to the pressure relief drill holes 16. In other words, each pressure relief drill hole 16 has a corresponding non-negative segment. Adjacent non-negative segments are connected by corresponding negative segments.

[0083] According to the formula The pressure relief radius R of each pressure relief borehole 16 was calculated.

[0084] In some embodiments, at least two pressure relief boreholes 16 have the same diameter. Or, some of the pressure relief boreholes 16 have the same diameter. Or, the diameter of each pair of pressure relief boreholes 16 is different.

[0085] For example, in such Figure 3 In the example shown, the multiple pressure relief boreholes 16 have three diameters, such as 65mm, 90mm, and 108mm, and there are at least two pressure relief boreholes 16 for each diameter. This allows the pressure relief radius R corresponding to the pressure relief boreholes 16 of the three diameters to be obtained simultaneously, and the pressure relief boreholes 16 of each diameter have at least two pressure relief radii R to corroborate each other.

[0086] Furthermore, the pressure relief boreholes 16 can also be configured as multiple rows arranged at intervals along the vertical direction.

[0087] In some embodiments, when the change in each strain value among the multiple strain value changes obtained in the subsequent acquisition is less than or equal to 1% compared to the change in strain value obtained at the same acquisition point in the previous acquisition, and each strain value change is negative or non-negative compared to the change in strain value obtained at the same acquisition point in the previous acquisition, it is considered that the multiple strain value changes obtained in the subsequent acquisition are all stable, and the acquisition of real-time strain values ​​is stopped.

[0088] The last acquisition before stopping the acquisition of real-time strain values ​​(in other words, the last acquisition mentioned above) yielded multiple strain value variations that were all stable and included alternating negative and non-negative segments, thus obtaining the arrangement length of the non-negative segment corresponding to the pressure relief borehole 16 on the sensing fiber 4.

[0089] It is understood that, in other embodiments, the variation of multiple strain values ​​obtained from the penultimate acquisition before stopping the acquisition of real-time strain values ​​can also be considered to have a stable average value, thereby obtaining alternating negative and non-negative segments.

[0090] In the description of this invention, it should be understood that the terms "center", "length", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0091] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0092] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0093] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0094] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for measuring the pressure relief range of a pressure relief borehole, characterized in that, include: Optical fiber arrangement holes are set in the rock mass, and sensing optical fibers are placed in the optical fiber arrangement holes. The optical fiber arrangement hole is sealed, and then grouting material is injected into the optical fiber arrangement hole; A pressure relief borehole is set in the rock mass, and the pressure relief borehole is located below the optical fiber arrangement hole; In the vertical projection plane, the distance between the projection of the pressure relief borehole and the projection of the optical fiber arrangement hole is 0.3m to 0.5m; when the pressure relief borehole is drilled in the roadway side of the rock mass, in the horizontal projection plane, the projection of the pressure relief borehole intersects with the projection of the optical fiber arrangement hole, and the depth of the pressure relief borehole from the roadway side is greater than the maximum distance between the optical fiber arrangement hole and the roadway side. When the grouting material solidifies, the initial strain value of the sensing optical fiber is collected by an optical time domain reflectometer. The optical time domain reflectometer collects real-time strain values ​​at multiple points on the sensing fiber, and collects them multiple times in sequence. The difference between each real-time strain value collected and the initial strain value is calculated to obtain the strain value variation corresponding to each collection. The collection of real-time strain values ​​is stopped when the strain value variation values ​​obtained in the same collection are all stable. The multiple strain value variations obtained from the same acquisition and with stable values ​​include alternating negative and non-negative segments. The negative segments include multiple strain value variations that are continuously negative, and the non-negative segments include multiple strain value variations that are continuously non-negative. The non-negative segments located between the beginning and the end of the negative segments correspond to the pressure relief borehole. According to the formula The pressure relief radius R of the pressure relief borehole is calculated, where h is the distance between the center point of the pressure relief borehole and the sensing optical fiber, and L is the length of the non-negative segment corresponding to the pressure relief borehole on the sensing optical fiber.

2. The method for measuring the pressure relief range of a pressure relief borehole according to claim 1, characterized in that, There are at least two pressure relief holes, and the at least two pressure relief holes are arranged at intervals along the length direction of the optical fiber arrangement hole. There are at least two non-negative segments located between the beginning and the end of the negative segments, and along the length direction of the optical fiber arrangement hole, at least two non-negative segments correspond sequentially to at least two pressure relief drill holes; According to the formula The pressure relief radius R of each of the pressure relief boreholes is calculated.

3. The method for measuring the pressure relief range of a pressure relief borehole according to claim 2, characterized in that, At least two of the aforementioned pressure relief boreholes have the same diameter; or In at least two of the aforementioned pressure relief boreholes, some of the boreholes have the same diameter; or In at least two of the aforementioned pressure relief boreholes, the diameter of each pair of the pressure relief boreholes is different.

4. The method for measuring the pressure relief range of a pressure relief borehole according to claim 1, characterized in that, When the change in strain value obtained in a subsequent acquisition is less than or equal to 1% compared to the change in strain value obtained in a previous acquisition at the same acquisition point, and when the change in strain value obtained in a previous acquisition at the same acquisition point is negative or non-negative, the acquisition of the real-time strain value is stopped. The strain values ​​obtained from the last acquisition before the acquisition of the real-time strain values ​​were stopped were all stable and included alternating negative and non-negative segments, thereby obtaining the length of the non-negative segment corresponding to the pressure relief borehole on the sensing optical fiber.

5. The method for measuring the pressure relief range of a pressure relief borehole according to claim 1, characterized in that, A chamber is constructed in the sidewall of the rock mass, and optical fiber arrangement holes are drilled in the wall of the chamber. The optical fiber arrangement holes extend parallel to or inclined along the sidewall, and the distance between the optical fiber arrangement holes and the sidewall is greater than or equal to 2m.

6. The method for measuring the pressure relief range of a pressure relief borehole according to claim 1, characterized in that, The sensing fiber is mounted on a flexible mounting tube, which is inserted into the fiber arrangement hole so that the sensing fiber is located in the fiber arrangement hole and extends from the opening of the fiber arrangement hole to the bottom of the hole.

7. The method for measuring the pressure relief range of a pressure relief borehole according to claim 6, characterized in that, After the mounting tube is inserted into the optical fiber arrangement hole, the grouting tube is inserted into the optical fiber arrangement hole and arranged side by side with the mounting tube. After the optical fiber arrangement hole is sealed, grouting material is injected into the optical fiber arrangement hole through the grouting pipe, and the injection of grouting material is stopped when the grouting material is discharged through the installation pipe.

8. The method for measuring the pressure relief range of a pressure relief borehole according to claim 1, characterized in that, The optical time-domain reflectometer is connected to the sensing fiber via a communication fiber to acquire the initial strain value and the real-time strain value of the sensing fiber; and / or The acquisition frequency of the optical time domain reflectometer is less than or equal to 0.1 m.

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